Dr Richard Kirby's book, "Ocean Drifters: A Secret World Beneath the Waves" showcases the beauty and diversity of plankton.

The perception of many is that plankton are just food for fish and whales, but in reality they are amongst the most important group of organisms in the world, where they underpin the marine food chain, provide incredible amounts of oxygen to the planet, and play an essential role in the global carbon cycle.

Phytoplankton, a form of algae that lives near the water surface, is eaten by larger zooplankton, providing carbon to the food web. Because this organic matter is denser than saltwater, the carbon sinks deep into the ocean — a process known as the biological pump.

Dr Kirby's book includes amazing high-magnification photography and details how plankton is being affected by global warming, potentially leading to disastrous consequences if these organisms drop in numbers.

Increasing global temperatures are raising the sea surface temperature. This is altering the plankton's habitat and changes their population, distribution and seasonality, explains the author.

"Without the plankton there would be no fish in the sea, or creatures that feed upon them," Dr Kirby says.